Method of producing gas



Feb. 19 1924.

C. LUNDIN METHOD OF PRODUCING G'AS Filed Jan.. 18 1922 3 Sheetsl-Sheet 1 FIE-L1.

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'% M W. x4 7 wnwessee Feb; 19 1924. 1,484,225 C.- LUNDIN METHOD OF PRODUCING Gas Filed Jan. 18 1922 5 Shee ts-Sheet 5 FIE.E.

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cant autumn; or rxrrssuaon, PENNSYLVANIA.

. mnrnon'or recover-us ens.

' To all whom it may mm.-

Be it known thatT, CARL LUNbiN', a citizen of the United States, and a resident of Pittsbur h, in the county of Allegheny and State of ennsylvania, have invented a new and useful Improvement in Methods of Producing Gas,"of which the following is a specification.

Theinvention relates to a method for pro-. ducing as. It relates particularly to a method or producing an artificial gas high in carbon monoxid and hydrogen.

- The usual fuel or producergas contains a "relatively high percentage of non-combustible elements which reduce the heat ef- Jficiency of the gas. The non-combustible component of these gases is mostly madeup ,of nitrogen which is present in the gas, due to the factthat the oxygen required for the ga'sification of the coal is taken from the atmosphere. It is important that a. simple, efficient method for producing gas be devised in which the gas produced is substantially free from nitrogen and high in desirable 2 combustible elements. In order to be commercially successful this process 'must're quire a' minimum amount of heat and must be simple so that a complicated apparatus is not required for carrying it out.- 4

One of the objects of the present invention is to provide an improved process 7 for producing a fuel gas which is substantially-free from nitrogen, has a-high percentage of combustible elements, and one in 3a which'the heatgenerated in the production of the. gas is utilized forcarrying out the process itself.

A ;-further object is to provide an improved process for producing a gas high in carbon monoxid and hydrogen and substantiallyf're'e from nitrogen by distilling carbona'ceous material, but of contact with air, and furnishing oxygen to the gases produced by means of ametallic oxid, the heat of the.

t6 combustion caused by the uniting of the oxygen of themetallic oxid with the gases produced-from the coal furnishing heat for carrying out the process.

Other objectsandadvantages will appear from the following specification.

A process similar to the one disclosed herein in which the gases were necessarily passed in buta single stream to effect oxidation and in which-the heat was absorbed in but a single stage after leaving the, carbonaceous maoxid (CO), hydro n 'terial was disclosedfand claimed in prior 1 application SerialfNo. 473, O4 6,'filed May 27, 1 921, ofwhichjthis application is a continua tion 1n part. 1 v

' Generally stated the process consists in the destructive distillation of carbonaceous material, such as coal, to pfoduce carbon monand other gases, the percentage 0 each depending on the quality of carbonaceous-material used; the as passing of these gases into contact with a metallic oxid, such as magnetic oxid of iron (Fe O,) to change the carbon monoxid-to carbon dioxid (00,), thereby producing heat for carrying out the entire process; and the subsequent passing'ofthe carbon dioxid over heated carbonaceous material to again change it to carbon monoxid; air being excluded from the entire process to exclude the non-combustible gases of the atmosphere, such as nitrogen, from the gas.

' The accompanying drawings show a form of apparatus for carrying out the process. In these drawings Fig. 1 1s a diagrammatic view illustrating the arrangement of the principal portions of the apparatus; Figs. 2, 3, and 4, illustrate the type of check valve used in the conduits of the apparatus, Fig. 3 showing the same in end elevation, and Figs. 2 and 4 showing the same in longitudinal section and showing the valve, respectively, in open and closed positions; Fig. 5 is a side elevation, parts bein shown in section, of'a detailed apparatus, t e essentials of which are diagrammatically shown in Fig. 1; and Fig. 6 is an end elevation of the same, parts being shown in section.

The apparatus-illustrated has two sets of coal retorts 1, 2, 3, and 4, and 5, 6, 7, and 8, respectively, which contain the coal or other carbonaceous material used in the production of the gas. The retorts 1 2, 3L, and 4, are connected at their bottoms and tops respectively by conduits 9 and 10 with the combustion chambers 11, 11, 11", and 11, and the retorts 5, 6, 7, and 8 are likewise connected at their bottoms and top; by conduits 12 (shown in dotted lines, Fig. 1) and 13 with similar combustion chambers 14 14, 14 and 14,

the two sets of combustion chambers being 1 connected at-their tops by a pipe 15 and the bottom conduits 9 and 12 by the transverse pipe 15'. These combustion chambers are arranged to contain a metallic oxid, such as the magnetic oxid of iron before mentioned. 110

, and 8, is also connected at bottom and top by conduits 23 and 24, with regenerative chambers25, 25', arranged in tandem which in turn are connected with a gas receivin receptacle 26 having a discharge pipe 2 and automatic relief valve 28. The receptacles 20 and 26 are respectively connected by conduits 30 and 31 with the casing of a reversing valve 32, which is connected to a pump 33. The pump operates continuously in one direction, and the valve 32 is automaticall and periodically operated to reverse the direction of flow of gas through the apparatus.

Both sets of coal retorts and oxid chambers are connected through valve controlled branch pipes, as clearly illustrated in the drawings, to the upper and lower gas conduits so that as many chambers as are desired may be connected or disconnected from the system. As illustrated the number of oxid chambers corres onds to that of the distillation retorts. uch an arrangement makes it possible to cut into or out of the system any desired number of retorts 01' combustion chambers thus securing economical operation and an exact balancing v of the system and effecting the chemical changes in the gases by passing the same in a plurality of small streams rather than a single one of greater volume, hence bringing the gases into more intimate contact with the carbonaceous material and oxides and securing anincreased efiiciency.

It is thus seen that two substantially symmetrical sets of coal retorts, ore or combustion chambers, and receptacles are provided which are connected together and associated with a pumping apparatus so that gas may be caused to flow from one to the other in the desired number of separate streams.

The apparatus is arranged so that no 7 matter in which direction the gas is flowing the flow is upwardly through both sets of coal retorts. In order to insure this direction of flow, check valves are arranged at suitable points in the system, as will be explained.

These check valves are illustrated in Figs. 2, 3, and 4. Each comprises a frame 34 carrying a bearing projection 35' in which is PIVOtGd' a valve member 36. When gas flows from left to right (as the valves are illustrated in the drawing) the valve memmesses check valves are illustrated inthe diagrammatic view Figs. 1, by sleeves on the conduits, the open and closed positions of the valves being indicated b circles on the to of the sleeves with a line through their diameter. When the line is parallel with the conduit it indicates that the valve is open, and when it is at right angles to the conduit, that the valve is closed.

With the check valves in the positions indicated in Fig. 1 the gas will flow from the first set of coal retorts 1, 2, 3, and 4 to the oxid chambers 11 to 11 and 14 to 14 and its course is as follows:

The pump 33 forces gas from the receptacle 20 through the chambers 19, 19', throughthe check valve 38, which is in open position, through the conduits 17 and 39 and upwardly through the coal retorts 1, 2, 3 and 4. The flow of gas from the chamber 19 upwardly through the conduit 18 is prevented by the check valve 40 which is closed when gas tends to fiow in this direction. The gas is also prevented from flowing directly from the conduit 17 through the conduit 9 to the ore chamber 11 to 11 by the check valve 41 which is closed when the gas tends to flow in such direction. Consequently the gas must flow upwardly through the first set of coal retorts, from which it passes through the conduit 10 and through a check valve 42, which is in open position, to the'ore chambers. The gas from the receptacle 20and the regenerative chambers thus passes upwardly through the first set of coal retorts to the ore chambers carto the conduit 12 while the remainmgpor-J tion flows through pipe 15 then downwardly through chambers 14 to 14 to conduit 12, the combined portions passing through check valve 43 to the pipes 44 and upwardly through the second set of coal retorts 5, 6, 7, and 8. Gas is prevented from flowing from the top of the chambers 14 to 14 and through the conduit 13 by a check valve '45 which is closed when the gas tends to flow in this direction. The gas is also prevented from flowing directly from the conduit 12 through the conduit 23 to the regenerative chambers 25, 25', by a 'check valve 46 which is closed when the gas tends to flow in this direction. Consequently the gas is forced to flow from the combustion chambers upwardly throughthe second'set of coal retorts and out through a check valve 47, which is in open position, to the conduit 24 and the regenerative chambers 25, 25', and receptacle 26. The gas is prevented from flowing back throu h check valve 45, because the pressure 0 the gas first set of coal retorts 1, 2, 3, and 4, and

through conduit 18 to the regenerative chambers 19, 19, and receptacle 20.

From this brief description of the apparatus it will be clear that a closed system has been provided in which the direction of flow of gas is periodically reversed and upon such reversals is caused to follow a definite course through the receptacles, regenerative chambers, coal retorts, and combustion chambers.

When the gas producing process is first started it is necessary to heat the retorts by some suitable means such as by initially burning a part of the coal in the retorts but, after the process has been started, it is no longer necessary to do so, the heat of the process itself being utilized for this pur ose.

T e coal retorts and also the other principal elements of the system are provided with heat insulating linings 50 which prevents material loss of heat by radiation, and provided with fire brick or otherrefractory material arranged to absorb the heat of the hot gases flowing therethrough and transfer the same to the coal for heating the latter. The coal retorts are arranged to have the coal charged into the same at the top, and the ashes and other refuse removed from the bottom, without admitting air thereto. As shown in Fig. 5 each retort is charged with coal from a storage receptacle 53, which receptacles communicate with the top of the retorts through conduits 54.- and valves 55, and which storage receptacles of each set are in turn supplied from a hopper 56 through pipes 57 and valve 58. When the retorts are to be charged the. valve 58 is opened and the storage receptacles 53 are filled with coal from the hopper 56, each storage receptacle preferably containing the proper quantity of coal for a single charge of the retort. Valve 58 isthen closed to prevent air entering the storage receptacles, and valve then 0 ened to admit the coal to the retort. Eac coal retort communicates through pipe 59 and valve 60 with a discharge hopper 61, common to the set, whereb the passage of ashes and other refuse rom the retort to the discharge hopper may be controlled at will.

The interiors of the oxid chambers ,11 to 11 and 14 to 14 are provided with a plurality of distributing passages, in the nature of ans 64 composed of specially shaped re racto'ry blocks which are provided with openings'therethrough, the successive pans being so located relative to one another that these pans are sta gered with relation to one another, there yproviding a series of irregular passages from the top to the bottom which causes the ore to be thoroughly distributed and causing a maximum amount of ore to be exposed to the gas. in said chamber.

The bottoms of the oxid chambers communicate through conduits 65 and valves 66 with discharge hoppers 67. The tops of these oxid chambers communicate through valves 68 and pipes 69 with stora e receptacles 70 which are supplied with t e metallic oxid from hoppers 71 through the distributing valves 72. Consequently each passage through the oxid chambers can be sup-' plied with a measured amount of oxid, from the receptacles 70, without admitting air,

and likewise the metallic iron resulting from the reduction of the oxid can be removed from the oxid chambers into the discharge receptacles 67 without admitting air.

Assuming thatthe retorts have been heated sufliciently for distillation and thatgas has been generated, in sufiicient quantity to drive all the air out of the system, the cycle,

of events is as follows The gas generated in the first set of coal retorts comprises principally carbon monoxid (CO) and hydrocarbons, but because of the limited amount of oxygen the volume of carbon monoxid is'relatively small. These gases pass to the sets of ore chambers where the carbon monoxid (CO) unites with the oxygen (0 of the iron oxid (Fe O,,) forming CO causing combustion to take place and producing heat which breaks up the hydroca'rbons and also raises the temperature of the gas.

The flow of gases from the coal retorts the combustion chambers causes the hot gases comprising (CO hydrogen (H nd other gases which were In the oxid chambers to be forced from the'chambers upwardly through the second set of coal retorts where the carbon dioxid (CO is converted into carbon monoxid (CO) when it comes in contact with the heated carbon or coal in the retorts.

The heat of the gases acquired in the comat a suitable temperature for carr ing out 26 a portion of them may escape through the process, the entire apparatus being heatinsulated by roviding the conduits and retorts with sultable magnesia linings.

The gases, which have passed throughthe second set of coal retorts, consist principally of carbon monoxid, hydrogen, and a small amountof other gases, and these ass.

to the regenerative chambers 25, 25, w ere their excess heat is absorbed by the checkerwork in the regenerative chambers as the gases flow therethrough to the receptacle 26. When the gases arrive in the receptacles the relief valve 28 to the storage tanks as the pressure of the gas generated in the system becomes sufficient to cause the gas'to flow through the relief valve; Other portions of the gas may flow in the reversing valve 32 and through the pump to the receptacle 20 and be further forced through the system. The timing of the reversing valve 32, however, is determined so that the gases pass approximately through only one cycle, after which the valve is reversed, caus-' ing them to flow in the opposite direction.

When the valve is reversed, the gases in receptacle 26 are forced through-the regenerative chambers 25, 25, where they are heated by the hot checker work in case they have lost any of their heat in the receptacle 26, and from the chambers 25, 25, they pass upwardly through the second set of coal retorts 5, 6, 7, and 8. The coal in this'set of retorts has been heated by the passage of hot gases therethrough and by the heat of the walls of the retorts and consequently gas is continually being generated from said coal. which gas flows with the other gases to the combustion chambers 14 to 14 and 1.1 to 11 where the carbon monoxid unites with the oxygen of the iron oxid to form C0,, producing heat and breaking up the hydrocarbons. The hot gases in the combustion chamber which came originally from the. first set of coal retorts are forced back to said retorts, where the heat of the gases is utilized to maintain the temperature of the coal and the retorts and the carbondi oxid is converted to carbon monoxid which flows with the'hydrogen and other gases to the regenerative chambers 19, 19', through the checker work therein which is heated by the passage of the gases to the receptacle 20.

It will thus be seen that the gases generated in the coal retorts, which gases oomprise principallycarbon monoxid and hydrogen substantially free of nitrogen, are passed to combustion chambers where oxygen is furnished to increase the volume of the gases, produce heat and break up the hydrocarbons- This increased volume of hot gases is then returned to the coal retorts, where the carbon dioxid is changed to carbon monoxid and at the same time the coal and the coal retorts are heated to a proper temperature to cause this change to take place and also todistil the coal.- The heat generated in the combustion chambers is utilized to heat the coal in the coal retorts by causing the gases to be periodically oscillated from the coal retorts to the oXid-chambers and back again. In other words, vit may be considered that, atone instant, gas is being generated in one set of coal retorts, passed to the sets of combustion chambers where its volume is increased and heat produced, and at the same time hot gases previously in the combus tion chambers are forced through the second' set of coal retorts to heat the retorts and coal and to convert the carbon dioxid into carbon monoxid. At the next instant the direction of flow is reversed and the hot gases in the combustion chambers are returned to the first set of coal retorts, where their condition is changed and their heat utilized for generating more gas from the coal; At the same time the gases generated in the second set of coal retorts are forced to the combustion chambers, where they unite with the oxygen of the iron oxid.

In addition, the heat of the gases is. con served by regenerative chambers arranged in tandem, which store the heat of the hot gases flowing out of the system and reconvey it to any gases flowing into the apparatus from the receptacles. The gases first enter regenerator 19 or 25 and then pass to the adjacent regenerator 19 or 25 from which it is delivered to the receptacles 20 or 26. By providing a series of small diameter and comparatively high regenerators arranged in tandems, an excellent abstraction of heat is effected, the second'regenerator always remaining at a. lower temperature than the initial regenerator to which the gas is led from the retorts.

The heat of the process is further conserved as follows The removal of the oxygen from the iron oxid in the combustion chambers leaves free iron, which is relatively hot and which, in its hot condition, is discharged from time to time to the atmosphere. As the free iron comes into contact with the air, it reoxidizes, forming iron oxid, and producing heat. As a matter of fact, when the iron discharges from the combustion chambers it is dark in color, but as soon as it comes in contact with the air it begins to glow as it unites with the oxygen to form iron oxid. The heat of the iron and the iron oxid is utilized for warming the coal charged into the coal retorts by causing the hot iron and iron oxid to pass through conduits or ore drums which are surrounded chambers are connected through valves 7 with discharge chutes 76 which discharge into ore drums 7 7, which are located relative to other drums 78, 79, and 80, all of which are provided with suitable screw or other conveyors so that the hot iron is first conveyed to the drums 77, carried the length thereof and then discharged into'the drums 78, carried back through the length of these drums, discharged to the third drums and so on, until from the last drum it is discharged into a pocket '81, from which the iron, which has now been again converted into iron oxid by exposure to the atmosghere, is carried by a bucket conveyor 82,

ack to the feeding hopper 71. The ore drums 77 7 8, 79, and 80, are located within a receiving pocket 83 which is normally kept filled with coal forcharging the coal retorts. The heat of the hot iron, as well as that produced by reoxidization of the iron as it passes through the ore drums is communicated to the coal surrounding these ore drums and consequently raises its tem-- perature preliminary to its productive distillation in the 'coal retorts. This coal is removed from the coal pocket 83 by the bucket conveyor 82 and distributed to the retort feed hoppers 56.

The iron oxid, after givingiup its heat. is again reconveyed to the apparatus for charging the combustion chambers and is used over again. The economy of this step of the process will be readily apparent and it will be noted that oxygen is furnished to the gas without permitting non-combustible elements to be supplied thereto at the same time and by means which may be used over and over again and by a process which generates heat that it utilized in carrying out the other steps of the process.

The heat of the free iron and of the oxidation of this iron also serves a useful purpose in eliminating the sulphur which comes from the coal. This sulphur is vaporized in the coal retorts and passes to the ore chambers where it forms sulphurous acid. This acid is discharged with the free iron and when the temperature of the iron is raised by oxidation it is decomposed, forming S0 which is a vapor, water, and oxygen. The heat in the combustion chambers 'is not suflicient to thus decompose the sulphurous acid, but the heat of the re-oxidation of the iron is sufficient to so decompose it. Consequently the iron oxid which is recharged into the combustion chambers is free from sulphurous acid and the procesfi; thus automatically eliminates the sulp ur.

From the foregoing description it will be clear that a process hasbeen devised by means of which a fuel gas rich in carbon monoxid and hydrogenbut substantiall free from non-combustible elements suc as nitrogen, is produced 1n an automatic and continuous manner and in such a way that the heat of the process is utilized for.

making the process self-sustaining, The sulphur in the coal is automatically eliminated and the oxygen carrying element is automatically regenerated so that it may be used over and over again. The process a is simple, economical, automatic, and continuous, as will be readily observed. Moreover, the size of the apparatus is reduced over that ordinarily required in such processes because of the fact that the oxygen is not furnished by means of air. Air is a mixture containing substantially one part of oxygen to four parts of nitrogen, 'and consequently an apparatus in which oxygen is furnished by the airmust be of sufficient size to accommodate four volumes of nitrogen to one Volume of oxygen.

The process is particularly economical and efiicient because of the utilization of the heat generated in furnishing the oxygen for carrying out the process, thus making the process self-sustaining and eliminating 'the expense of heating the various retorts and chambers, as heretofore required.

It is to be. understood that variations may be made in the exact manner of practicing' the-process, such variations being includedwithin -the scope of the appended claims.

What is claimed is 1. The method of producing gases .rich in carbon monoxid and hydrogen but substantially free of nitrogen, which consists in distilling carbonaceous material without exposing the same to air, passing the resulting gases into contact with a metallic oxid to furnish oxygen to the gases and produce heat, repassing the hot oxidized gases into contact with the carbonaceous material to furnish carbon to the gases, and passing the free metal resulting from the oxidation of the gases into heat exchanging relation with the carbonaceous material used in the process to warm said carbonaceous material and utilize the heat of the metal.

2. The method of producing gases rich in carbon monoxid and hydrogen but sub-v stantially free of nitrogen, which consists in distilling coal without exposingthe same to air, passing the resulting gases into contact with an iron oxid to furnish oxygen to the gases and produce heat, vrepassing the hot oxidized gases into contact with the coal to furnish carbon to the gases and heat the coal, and passing the free iron resulting from the oxidation of the gases into heat exchanging relation with the coal used in ing from the distillation into contact with a metallic oxid to furnish oxygen to the gases and produce heat, passing hot oxidized gases into contact with carbonaceous material to furnish carbon to the gases and heat the carbonaceous material, periodically reversing the direction of flow of the gases whereby the heat generated in oxidizing them is utilized for heating the carbonaceous material,

and passing the heated metal resulting from the oxidation of the gases into heat exchanging relation with the carbonaceous material used in the process. I 4. The method of producing gases rich in carbon monoxid and hydrogen but substantially free of nitrogen, which consists in distilling coal in closed retorts without exposing the coal to air, passing the resulting gases into contact with a metallic oxid in a closed chamber to furnish oxygen to the gases and produce heat, passing the hot oxidized gases into contact with the coal in the closed retorts to furnish carbon to the gases and heat the coal, periodically reversing the direction of flow of the gases whereby the heat generated in oxidizing them is utilized for heating the coal, passing the metal resulting from the removal of the oxygen from the metallic oxid into heat exchanging relation with the coal used in the process and exposing said metal to air whereby the metal is changed into a metallic oxid and its heat absorbed by the coal, periodically supplying the warm carbonaceous material to the retorts, and periodically supplying the revived metallic oxid to the oxid chambers.

5. The method of producing a gas rich in carbon monoxid and hydrogen and substantially free of nitrogen, which consists in producing gases by distilling carbonaceous material out of contact with air, furnishing oxygen to said gases and generating heat by passing the same in a plurality of divided streams into contact with a metallic oxid, passing the hot gases into contact with carbonaceous material and subsequently through an excess heat-absorbing chamber, and periodically reversing the direction of flow of the gases whereby the heat of oxidacarbon monoxid and hydrogen ut-substantially free of nitrogen which consists in distilling carbonaceous material without exposure to air, passing the resulting gases in a plurality of separate streams into contact with a metallic oxid to furnish oxygen to the gases and produce heat, repassing the hot oxidized gases into contact with the carbonaceous material to furnish carbon to the gases, and passing the free metal resulting from the oxidation of the gases into heat exchanging relation with the carbonaceous material used in the process to warm said material and utilize the heat ofthe metal.

7.. The method of producing a gas rich in carbon monoxid and hydrogen and substantially free of nitrogen, which consists in producing gases by distilling carbonaceous material out of contact with air, furnishing oxygen to said gases and generating heat by passing the same in a plurality of divided streams into contact with a metallic oxid, passing the hot gases into contact with carbonaceous material and subsequently through excess heat-absorbing chambers ar-- ranged in tandem, periodically reversing the direction of flow of the gases to utilize the heat of oxidation to distill the carbonaceous material, and passing the free metal resulting from the oxidation of the gases into heat exchanging relation with the carbonaceous material to warm said material and utilize the heat of the metal.

8. The method of producing a gas rich in carbon monoxid and hydrogen and substantially free of nitrogen. which consists in producing gases by distilling carbonaceous material out of contact with air, furnishing oxygen to said gases andgenerating heat by passing the same into contact with metallic oxid in the formof iron ore, passing the hot gases into contact with carbonaceous material, periodically reversing the direction of flow of the gases to utilize the heat of oxidation for distilling ,the carbonaceous material without the necessity of applying external heat, and periodically removing the sulphur content of the iron ore by oxidizing the metal resulting from the oxidation by exposing the same to the atmosphere.

In testimony whereof, I sign my name.

CARL LUNDIN.

Witness:

EDWIN O. JOHNS. 

